/*
8. Write an expression that calculates trapezoid's area by given sides a and b and height h.
*/
using System;

class zadachaOsma
{
    static void Main()
    {
        Console.Write("Enter side a: ");
        double sideA = double.Parse(Console.ReadLine());
		
		Console.Write("Enter side b: ");
        double sideB = double.Parse(Console.ReadLine());
		
		Console.Write("Enter height h: ");
        double heightH = double.Parse(Console.ReadLine());
		
        Console.WriteLine("The area of trapezoid is: {0}", 0.5*(sideA + sideB) * heightH);
    }
}
